Method read_f32

crates/virtual-machine/src/cpu/registers.rs:62–68

Reads the register as an f32, applying NaN-boxing validation. If bits [63:32] are not all 1s the stored value is not a valid NaN-boxed f32, so the canonical NaN is returned (RISC-V spec 11.3).

(&self, reg: usize)

    pub fn read_f32(&self, reg: usize) -> f32 {
        let bits = self.f[reg];
        if bits & NAN_BOX_UPPER != NAN_BOX_UPPER {
            return f32::NAN;
        }
        f32::from_bits(bits as u32)
    }

    /// Writes an f32, NaN-boxing it by setting bits `63:32` to all 1s.
    pub fn write_f32(&mut self, reg: usize, val: f32) {
        self.f[reg] = NAN_BOX_UPPER | u64::from(val.to_bits());
    }